tonight's headliner is first lady michelle obama. she speaks in about two hours. in charlotte, ken pritchett, ktvu channel 2 news. >>> and ktvu is streaming the dnc convention live when we're not on the air. just download the mobile app to your phone or tablet and click on the live streaming button. >>> new research showing social networking sites have only a modest influence on views. the research found 80% of users have posted little or nothing related to politics on-sites such as facebook and twitter. social networking is called varied or some what in keeping up the -- >>> an anti soda tax is suing richmond. the ordnance requires mass mailings to include funding information right on the front page. the coalition is funded mostly by the american beverage association. >>> san francisco transit officials are taking a closer look at a consider sharing program that some say is just a way to get around city taxi laws. new at 6:00, david stevenson is live now in san francisco with the unusual ride that is drawing scrutiny, david. >> reporter: julie, it's notoriously d